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Biomedical subjects

P Williamson

Publications and source records attributed to P Williamson.

At least 19 recordsLinked to original sources
PubMed2006

Portosystemic shunts versus endoscopic therapy for variceal rebleeding in patients with cirrhosis.

BACKGROUND: Randomised clinical trials have compared portosystemic shunting procedures with endoscopic therapy for variceal haemorrhage, but there is no consensus as to which approach is preferable. OBJECTIVES: To compare the effects of shunts (total surgical shunt (TS); distal spleno-renal shunts (DSRS) or transjugular intrahepatic porto-systemic shunts (TIPS) with endoscopic therapy (ET, sclerotherapy and/or banding) for prevention of variceal rebleeding in patients with cirrhosis. SEARCH STRATEGY: The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Library, MEDLINE, EMBASE, conference proceedings, and the references of identified trials were searched (last search February 2004). Researchers in the field and in industry were contacted. SELECTION CRITERIA: Randomised clinical trials comparing TS, DSRS or TIPS with ET in patients who had recovered from a variceal haemorrhage and were known to be cirrhotic. DATA COLLECTION AND ANALYSIS: Data were collected to allow intention-to-treat analysis where possible. For each outcome, a pooled estimate of treatment effect (log hazard ratio for time to outcome, Peto odds ratio for binary outcomes, and differences in means for continuous outcomes) across trials was calculated. MAIN RESULTS: Twenty-two trials evaluating 1409 patients were included. All trials had problems of method. Shunt therapy compared with ET demonstrated significantly less rebleeding (OR 0.24, 95% CI 0.18 to 0.30) at the cost of significantly increased acute hepatic encephalopathy (OR 2.07, 95% CI 1.59 to 2.69) and chronic encephalopathy (OR 2.09, 95% CI 1.20 to 3.62). There were no significant differences regarding mortality (hazard ratio 1.00, 95% CI 0.82 to 1.21) and duration of in-patient stay (weighed mean difference 0.78 day, 95% CI -1.48 to 3.05). The proportion of patients with shunt occlusion or dysfunction was 3.1% (95% CI 0.4 to 10.7%) following TS (two trials), 7.8% (95% CI 3.8 to 13.9%) following DSRS (four trials), and 59% (range 18% to 72%) following TIPS (14 trials). AUTHORS' CONCLUSIONS: All shunts resulted in a significantly lower rebleeding rate at the expense of a higher incidence of encephalopathy. TIPS was complicated by a high incidence of shunt dysfunction. No survival advantage was demonstrated with any shunt.

Endoscopy↗
PubMed2006

Does sodium hyaluronate- and carboxymethylcellulose-based bioresorbable membrane (Seprafilm) decrease operative time for loop ileostomy closure?

BACKGROUND: Adhesions can result in serious clinical complications and make ileostomy closure, which is relatively simple procedure into a complicated and prolonged one. The use of sodium hyaluronate and carboxymethyl cellulose membrane (Seprafilm) was proven to significantly reduce the postoperative adhesions at the site of application. The aim of this study was to assess the incidence and severity of adhesions around a loop ileostomy and to analyze the length of time and morbidity for mobilization at the time of ileostomy closure with and without the use of Seprafilm. METHODS: Twenty-nine surgeons from 15 institutions participated in this multicenter prospective randomized study. 191 patients with loop ileostomy construction were randomly assigned to either receive Seprafilm under the midline incision and around the stoma (Group I), only under the midline incision (Group II), or not to receive Seprafilm (Group III). At ileostomy closure, adhesions were quantified and graded; operative morbidity was also measured. RESULTS: All 3 groups were comparable relative to gender, mean age and number of patients with prior operations (26, 25 and 19, respectively). Group II patients were significantly more likely to have pre-existing adhesions than Group III patients (30.6% vs. 14.1%, p = 0.025). At stoma mobilization, significantly more patients in Group III than in Group I had adhesions around the stoma (95.2% vs. 82.3%, p = 0.021). Mean operative times were 27, 25, and 28 minutes, respectively (p = 0.38), with significant differences among sites. There was no significant difference in the number of patients needing myotomy or enterotomy (29, 27 and 24 patients, respectively), nor in the number of postoperative complications (7, 9 and 7 patients, respectively). CONCLUSIONS: When consistently applied, Seprafilm significantly decreased adhesion formation around the stoma but not operative times without any increase in the need for myotomy or enterotomy. These findings were not seen in the overall study population possibly due to the large number of surgeons using a variety of application techniques.

Adjuvants, Immunologic↗
PubMed2006

Risk stratification in acute coronary syndromes--does the TIMI risk score work in unselected cases?

BACKGROUND: Management of patients with an acute coronary syndrome (ACS) requires accurate risk stratification to guide appropriate therapy. AIM: To assess the utility of the TIMI risk score in stratifying patients with possible ACS in routine clinical practice. DESIGN: Prospective observational study. METHODS: We recruited 869 consecutive patients with a diagnosis of possible ACS attending the acute medical receiving unit of a district general hospital. The main outcome measures were recurrent myocardial infarction, urgent revascularization, and all-cause mortality. TIMI risk score was calculated for each patient, and each was also assigned a risk group based on electrocardiogram (ECG) changes and troponin levels only. After follow-up, Cox univariate and multivariate regression was used to evaluate the influence of potential risk factors on duration of event-free survival, and likelihood ratio tests to assess the fit of the models. RESULTS: Increasing TIMI risk score was associated with increased risk of events (p<0.001), as was higher risk group from ECG plus troponin stratification (p<0.001). The likelihood ratio comparison favoured the TIMI risk score (difference 13.910, 5 degrees of freedom, p = 0.016). DISCUSSION: The TIMI risk score is a valid tool for risk stratification in unselected cases with possible acute coronary syndrome. It is superior to ECG changes and troponin alone, although this simpler method also achieves good risk stratification.

Adolescent↗
PubMed2005

HIV and male circumcision--a systematic review with assessment of the quality of studies.

This Cochrane systematic review assesses the evidence for an interventional effect of male circumcision in preventing acquisition of HIV-1 and HIV-2 by men through heterosexual intercourse. The review includes a comprehensive assessment of the quality of all 37 included observational studies. Studies in high-risk populations consisted of four cohort studies, 12 cross-sectional studies, and three case-control studies; general population studies consisted of one cohort study, 16 cross-sectional studies, and one case-control study. There is evidence of methodological heterogeneity between studies, and statistical heterogeneity was highly significant for both general population cross-sectional studies (chi(2)=132.34; degrees of freedom [df]=15; p<0.00001) and high-risk cross-sectional studies (chi(2)=29.70; df=10; p=0.001). Study quality was very variable and no studies measured the same set of potential confounding variables. Therefore, conducting a meta-analysis was inappropriate. Detailed quality assessment of observational studies can provide a useful visual aid to interpreting findings. Although most studies show an association between male circumcision and prevention of HIV, these results may be limited by confounding, which is unlikely to be adjusted for.

Africa South of the Sahara↗
PubMed2005

Pleomorphic adenoma and severe obstructive sleep apnoea.

Two cases of deep lobe parotid tumours extending into the parapharyngeal space and causing obstructive sleep apnoea are described. Post-operatively, marked improvements in nocturnal hypoxic episodes and the symptoms of obstructive sleep apnoea were seen. Although minor salivary gland pleomorphic adenomas have been described as a cause of airway compromise, pleomorphic adenomata arising from the deep lobe of the parotid, causing proven obstructive sleep apnoea, have not previously been documented. The anatomy and common pathologies of the parapharyngeal space are discussed.

Adenoma, Pleomorphic↗
PubMed2004

Common antiepileptic drugs in pregnancy in women with epilepsy.

BACKGROUND: The potential adverse effects of antiepileptic drug (AED) exposure in pregnancy have been well recognised but the relative risks of specific antiepileptic drug exposures remain poorly understood. OBJECTIVES: To assess the adverse effects of commonly used antiepileptic drugs on maternal and fetal outcomes in pregnancy in women with epilepsy. Comparison of outcomes following specific antiepileptic drug exposures in utero to unexposed pregnancies in the general population or women with epilepsy are described. The current manuscript reports the first phase of this review which focuses upon neurodevelopmental outcomes in children exposed to antiepileptic drugs in utero. SEARCH STRATEGY: We searched MEDLINE, Pharmline, EMBASE, Reprotox and TERIS from 1966 to December 2003. Review articles and conference abstracts were also hand searched. SELECTION CRITERIA: All randomized controlled trials, prospective cohorts of children of pregnant women with and without epilepsy and case control studies (cases: developmental delay or impaired cognitive outcome, control: normal development) were included. DATA COLLECTION AND ANALYSIS: Methodological quality was assessed using an adapted version of the Newcastle-Ottawa Scale. The wide variety of outcome measures and methodological approaches made meta-analysis difficult and a descriptive analysis of the results is presented. MAIN RESULTS: PART A 1b - DEVELOPMENTAL OUTCOMES: The majority of studies were of limited quality. There was little evidence about which specific drugs carry more risk than others to the development of children exposed in utero. The results between studies are conflicting and while most failed to find a significant detrimental outcome with in utero exposure to monotherapy with carbamazepine, phenytoin or phenobarbitone, this should be interpreted cautiously. There were very few studies of exposure to sodium valproate. Polytherapy exposure in utero was more commonly associated with poorer outcomes, as was exposure to any AEDs when analysis did not take into account type of AED. The latter may reflect the large proportion of children included in these studies who were in fact exposed to polytherapy. REVIEWERS' CONCLUSIONS: PART A 1b - DEVELOPMENTAL OUTCOMES: Based on the best current available evidence it would seem advisable for women to continue medication during pregnancy using monotherapy at the lowest dose required to achieve seizure control. Polytherapy would seem best avoided where possible. More population based studies adequately powered to examine the effects of in utero exposure to specific monotherapies which are used in everyday practice are required.

Abnormalities, Drug-Induced↗
PubMed2004

Cost of illness of inflammatory bowel disease in the UK: a single centre retrospective study.

BACKGROUND AND AIMS: The potentially high costs of care associated with inflammatory bowel disease (IBD) are recognised but we have little knowledge of the scale, profile, or determinants of these costs in the UK. This study aimed to describe costs of illness for a group of IBD patients and determine factors associated with increased healthcare costs. SETTING: A university hospital serving a target population of approximately 330 000. PATIENTS AND METHODS: A six month cohort of IBD patients receiving any form of secondary care was identified, comprising 307 cases of ulcerative (or indeterminate) colitis and 172 cases of Crohn's disease. Demographic and clinical data were abstracted from clinical records and individual resource use was itemised for all attributable costs (including extraintestinal manifestations). Item costs were derived from national and local sources. Cost data were expressed as mean six month costs per patient (with 95% confidence interval (CI)) obtained using non-parametric bootstrapping. Determinants of cost were analysed using generalised linear regression modelling. A postal survey of patients was undertaken to examine indirect costs, out of pocket expenses, and primary care visits. RESULTS: Inpatient services (medical and/or surgical) were required by 67 patients (14%) but accounted for 49% of total secondary care costs. Drug costs accounted for less than a quarter of total costs. Individual patient costs ranged from 73 to 33,254 UK pounds per six months. Mean (95% CI) six month costs per patient were 1256 UK pounds ( 988 pounds, 1721 pounds) for colitis and 1652 UK pounds (1221 pounds, 2239 pounds) for Crohn's disease. Hospitalisation, disease severity grade, and disease extent correlated positively with cost of illness but costs were independent of age or sex. Compared with quiescent cases of IBD, disease relapse was associated with a 2-3-fold increase in costs for non-hospitalised cases and a 20-fold increase in costs for hospitalised cases. Survey data suggested average six month costs were < 30 UK pounds per patient for primary care visits (both diseases) and median loss of earnings were 239 UK pounds for colitis and 299 UK pounds for Crohn's disease. CONCLUSIONS: This study represents the first detailed characterisation of the scale and determinants of costs of illness for IBD in a British hospital. Hospitalisation affected a minority of sufferers but accounted for half of the total direct costs falling on the healthcare system.

Adult↗
PubMed2004

Coronary artery stents: a rapid systematic review and economic evaluation.

OBJECTIVES: To assess the effectiveness and cost-effectiveness of the use of coronary artery stents in patients with coronary heart disease (CHD). DATA SOURCES: Electronic databases. REVIEW METHODS: The review was conducted following accepted guidelines for conducting systematic reviews. Randomised controlled trials that include comparisons of percutaneous transluminal coronary angioplasty (PTCA) versus PTCA with stent, stent versus coronary artery bypass graft (CABG), and drug-eluting stents (DES) versus non-DES in patients with CAD in native or graft vessels and those with stable angina or acute coronary syndrome (ACS) and unstable angina were also included. Data on the following outcome measures were included in the review: combined event rate or event-free survival, death, acute myocardial infarction, target vessel revascularisation, repeat treatment (PTCA, stent or CABG) and binary restenosis. An economic model was developed based on extrapolation of trends in mortality and revascularisation from clinical trials data to a 5-year time horizon. RESULTS: The inclusion criteria were fulfilled by 50 studies comparing the use of stents with PTCA, six comparing stents with CABG and 12 comparing DES eluting stents with non-DES. No studies were identified that compared DES with PTCA or DES with CABG. Existing quality of life data suggest that revascularisation procedures reduce the patient's quality of life for a short period only. Stents were found to be more effective than PTCA in preventing adverse events and revascularisations. In multiple-vessel disease there was no evidence of a difference in mortality (at 1 year) between patients treated surgically and those receiving a stent. Patients treated surgically required fewer revascularisations. There is no evidence of a difference in mortality between patients receiving DES and those treated with bare metal stents at 1 year. A reduction in event rate at 9 and 12 months was found in patients treated with DES. This event rate is primarily made up of increased revascularisation rates in patients treated with bare metal stents. Two-year outcome data from one study indicate that this benefit of DES continues over the longer term. The economic model proved sufficient to indicate long-term trends in cost-effectiveness. CABG was found initially to be more expensive than bare metal stenting in multivessel disease and may have higher immediate risks, but over time the cost differential is reduced and long-term outcomes favour CABG over stenting. A similar situation was found for DES versus CABG in multiple-vessel disease. However, DES may not generally be considered a cost-effective alternative to bare metal stenting in single-vessel disease by policy makers as substantially higher costs are involved with a very small outcome benefit. CONCLUSIONS: DES might be considered cost-effective if the additional cost (compared with ordinary stents) was substantially reduced, the outcome benefits from the use of DES were much improved, and/or its use were targeted on the subgroups of patients with the highest risks of requiring reintervention. Long-term clinical studies are needed that focus on significant outcomes such as mortality. Further research should consider: the differences among plain stents; head-to-head comparisons within DES, CABG compared with DES; and the evaluation of newer non-DES against DES. Evaluation of the effects of revascularisation procedures and especially repeat revascularisation procedures on the patient's quality of life would also be useful, as would the development and testing of risk assessment tools to identify patients likely to need further revascularisations.

Angioplasty, Balloon, Coronary↗
PubMed2003

Practice parameter: temporal lobe and localized neocortical resections for epilepsy: report of the Quality Standards Subcommittee of the American Academy of Neurology, in association with the American Epilepsy Society and the American Association of Neurological Surgeons.

OBJECTIVES/METHODS: To examine evidence for effectiveness of anteromesial temporal lobe and localized neocortical resections for disabling complex partial seizures by systematic review and analysis of the literature since 1990. RESULTS: One intention-to-treat Class I randomized, controlled trial of surgery for mesial temporal lobe epilepsy found that 58% of patients randomized to be evaluated for surgical therapy (64% of those who received surgery) were free of disabling seizures and 10 to 15% were unimproved at the end of 1 year, compared with 8% free of disabling seizures in the group randomized to continued medical therapy. There was a significant improvement in quantitative quality-of-life scores and a trend toward better social function at the end of 1 year for patients in the surgical group, no surgical mortality, and infrequent morbidity. Twenty-four Class IV series of temporal lobe resections yielded essentially identical results. There are similar Class IV results for localized neocortical resections; no Class I or II studies are available. CONCLUSIONS: A single Class I study and 24 Class IV studies indicate that the benefits of anteromesial temporal lobe resection for disabling complex partial seizures is greater than continued treatment with antiepileptic drugs, and the risks are at least comparable. For patients who are compromised by such seizures, referral to an epilepsy surgery center should be strongly considered. Further studies are needed to determine if neocortical seizures benefit from surgery, and whether early surgical intervention should be the treatment of choice for certain surgically remediable epileptic syndromes.

Anticonvulsants↗
PubMed2003

Male circumcision for prevention of heterosexual acquisition of HIV in men.

BACKGROUND: The findings from observational studies, reviews and meta-analyses, supported by biological theories, that circumcised men appear less likely to acquire human immunodeficiency virus (HIV) has contributed to the recent ground swell of support for considering male circumcision as a strategy for preventing sexually acquired infection. We sought to elucidate and appraise the global evidence from published and unpublished studies that circumcision can be used as an intervention to prevent HIV infection. OBJECTIVES: 1) To assess the evidence of an interventional effect of male circumcision for preventing acquisition of HIV-1 and HIV-2 by men through heterosexual intercourse 2) To examine the feasibility and value of performing individual person data (IPD) meta-analysis SEARCH STRATEGY: We searched online for published and unpublished studies in The Cochrane Library (issue 2, 2002), MEDLINE (April 2002), EMBASE (February 2002) and AIDSLINE (August 2001). We also searched databases listing conference abstracts, scanned reference lists of articles and contacted authors of included studies. SELECTION CRITERIA: We searched for randomized and quasi-randomized controlled trials of male circumcision or, in their absence, observational studies that compare acquisition rates of HIV-1 and HIV-2 infection in circumcised and uncircumcised heterosexual men. DATA COLLECTION AND ANALYSIS: Independent reviewers selected studies, assessed study quality and extracted data. We stratified studies based on study design and on whether they included participants from the general population or high-risk groups (such as patients treated for sexually transmitted infections). We expressed findings as crude and adjusted odds ratios (OR) together with their 95% confidence intervals (CI) and conducted a sensitivity analysis to explore the effect of adjustment on study results. We investigated whether the method of circumcision ascertainment influenced study outcomes. MAIN RESULTS: We identified no completed randomized controlled trials. Three randomized controlled trials are currently underway or commencing shortly. We found 34 observational studies: 16 conducted in the general population and 18 in high-risk populations. It seems unlikely that potential confounding factors were completely accounted for in any of the included studies. In particular, important risk factors, such as religion and sexual practices, were not adequately accounted for in many of the included studies. General population study results:The single cohort study (N = 5516) showed a significant difference in HIV transmission rates between circumcised and uncircumcised men [OR = 0.58; 95% CI: 0.36 to 0.96]. Results for the 14 cross-sectional studies were inconsistent, with point estimates for unadjusted odds ratios varying between 0.28 and 1.73. Six studies had statistically significant results, four in the direction of benefit and two in the direction of harm. The test for heterogeneity between the cross-sectional studies was highly significant (chi-square = 77.59; df = 13; P-value < 0.00001). Nine studies reported adjusted odds ratios with eight in the direction of benefit, ranging from 0.26 to 0.80. Use of adjusted results tended to show stronger evidence of an association although they remained heterogenous (chi-square = 75.2; df = 13; P-value < 0.00001). Only one case-control study was found (N = 51) which had a non-significant result [OR = 1.90; 95% CI: 0.50 to 7.20]. High-risk group study results:The four cohort studies identified found a protective effect from circumcision with point estimates for unadjusted odds ratios varying from 0.10 to 0.39. Two of these studies had statistically significant results. Two studies reported adjusted odds ratios, both protective with one being significant. The chi-square test for between-study heterogeneity was not significant (chi-square = 5.21; df = 3; P-value = 0.16). All eleven cross-sectional studies reporting unadjusted results found benefit from circumcision, eight of which had statistically significant results. Estimates of effnal studies reporting unadjusted results found benefit from circumcision, eight of which had statistically significant results. Estimates of effect varied from an unadjusted odds ratio of 0.10 to 0.66. Between-study heterogeneity was significant with the chi-square = 29.77; df = 10; P-value = 0.0009. Four of these studies reported adjusted odds ratios ranging from 0.20 to 0.59 and all were significant. One additional cross-sectional study only reported an adjusted odds ratio in the direction of benefit which was statistically significant. All three case-control studies found a protective effect of circumcision on HIV status, two being statistically significant. Point estimates varied from unadjusted odds ratios of 0.37 to 0.88. One reported an adjusted odds ratio showing a significant protective effect. Adverse effects:No studies reported on the adverse effects of circumcision. In most studies, circumcision had taken place during childhood or adolescence before the studies commenced. REVIEWER'S CONCLUSIONS: We found insufficient evidence to support an interventional effect of male circumcision on HIV acquisition in heterosexual men. The results from existing observational studies show a strong epidemiological association between male circumcision and prevention of HIV, especially among high-risk groups. However, observational studies are inherently limited by confounding which is unlikely to be fully adjusted for. In the light of forthcoming results from RCTs, the value of IPD analysis of the included studies is doubtful. The results of these trials will need to be carefully considered before circumcision is implemented as a public health intervention for prevention of sexually transmitted HIV.

Circumcision, Male↗
PubMed2003

A note on the fetal-infant mortality problem.

This paper considers the age pattern of mortality between conception and first birthday. It highlights the various problems that still limit our understanding of the ways in which the age components of mortality are associated, especially during the perinatal period. A mathematical function is fitted which captures the interaction between six mortality components for a typical high mortality society, one in which the infant mortality rate is 150 per thousand live births. This experiment helps to clarify the need to link infant with fetal mortality, to conduct further research on the level of risk in each component, and to consider the cumulative early-age mortality profile in its entirety.

Fetal Death↗
PubMed2002

Coagulation changes in individuals with sickle cell trait.

Sickle cell disorders, such as Hb SS and Hb SC, are associated with a hypercoagulable state that may contribute to the vaso-occlusive episodes observed in the disorders. To what extent increased coagulation activity occurs in individuals with sickle cell trait has had limited study. Because such information may help clarify clinical and pathologic findings that may occur in these individuals and may be useful in clarifying the hypercoagulable state in sickle cell disease, we have examined individuals with Hb AS to determine the extent that increased coagulation activity does occur. We measured d-dimers, thrombin-antithrombin (TAT) complexes, prothrombin fragment 1.2 (F1.2), absolute blood monocyte levels, proteins C and S, and isotypes of antiphospholipid antibodies in individuals with Hb AS and in matched controls (Hb AA). Results showed that d-dimers, TAT, and F1.2 were increased significantly above normal levels. Absolute blood monocyte levels were increased. The d-dimers, TAT, F1.2, and monocyte counts showed significant increasing trends through groups of increasing severity (Hb AA, Hb AS, Hb SC, and Hb SS). Our study shows that individuals with Hb AS have increased coagulation activity, with d-dimers, TAT, and F1.2 being consistent indicators. The measures of coagulation activity in Hb AS are lower than in patients with Hb SC and Hb SS disease. These results extend our previous observation that the degree of coagulation activation parallels the degree of disease severity among sickle cell genotypes. The findings suggest that monocytosis, with the possible expression of monocyte-derived tissue factor, and the associated hypercoagulable state are driven by disease severity.

Adult↗
PubMed2001

Phospholipid scramblase activation pathways in lymphocytes.

In erythrocytes and platelets, activation of a nonspecific lipid flipsite termed the scramblase allows rapid, bidirectional transbilayer movement of all types of phospholipids. When applied to lymphoid cells, scramblase assays reveal a similar activity, with scrambling rates intermediate between those seen in platelets and erythrocytes. Scrambling activity initiated in lymphoid cells by elevation of intracellular Ca(2+) proceeds after a lag not noted in platelets or erythrocytes. The rates of transbilayer movement of phosphatidylserine and phosphatidylcholine analogues are similar whether the scramblase is activated by elevated internal Ca(2+) or by apoptosis. Elevation of internal Ca(2+) levels in apoptotic cells does not result in an additive increase in the rate of lipid movement. In lymphoid cells from a patient with Scott syndrome, scramblase cannot be activated by Ca(2+), but is induced normally during apoptosis. These findings suggest that Ca(2+) and apoptosis operate through different pathways to activate the same scramblase.

4-Chloro-7-nitrobenzofurazan↗
PubMed2001

Overexpression of E2F-1 leads to cytokine-independent proliferation and survival in the hematopoietic cell line BaF-B03.

Cytokine receptors activate signals that regulate the transcription factor E2F-1, which then coordinates the expression of genes essential for DNA synthesis and cell cycle progression. Overexpression of E2F-1 most often induces S-phase entry followed by apoptosis, but in some cell types it leads to continuous proliferation and transformation. Here, it is shown that constitutive expression of E2F-1 promotes cytokine-independent proliferation in the murine pro-B cell line BaF-B03. There was no enhancement of apoptosis following cytokine withdrawal in these cells, despite the presence of intact p53-dependent apoptotic pathways. Notwithstanding the continuous presence of E2F-1, the cell cycle-dependent expression of cyclin A, cyclin B1, cyclin D1, cyclin E, and proliferating-cell nuclear antigen was restored with a pattern equivalent to that associated with cytokine stimulation. These findings provide evidence that, in the absence of cytokine, constitutive expression of E2F-1 can promote cell cycle progression and prevent apoptosis.

Animals↗
PubMed2001

Corticobasal syndrome with tau pathology.

Six cases with a clinical corticobasal syndrome (progressive asymmetric apraxia and parkinsonism unresponsive to levodopa) and tau pathology were selected from 97 brain donors with parkinsonism. Postmortem volumetric measures of regional brain atrophy (compared with age/sex-matched controls) were correlated with clinical features and the degree of underlying cortical and subcortical histopathology. At death, no significant asymmetry of pathology was detected. All cases had prominent bilateral atrophy of the precentral gyrus (reduced by 22-54%) with other cortical regions variably affected. Subcortical atrophy was less severe and variable. Two cases demonstrated widespread atrophy of basal ganglia structures (44-60% atrophy of the internal globus pallidus) and substantial subcortical pathology consistent with a diagnosis of progressive supranuclear palsy (PSP). The remaining four cases had typical pathology of corticobasal degeneration. In all cases, neuronal loss and gliosis corresponded with subcortical atrophy, while the density of cortical swollen neurons correlated with cortical volume loss. Atrophy of the internal globus pallidus was associated with postural instability, while widespread basal ganglia histopathology was found in cases with gaze palsy. This study confirms the involvement of the precentral gyrus in the corticobasal syndrome and highlights the variable underlying pathology in these patients.

Aged↗